U.S. patent application number 11/639471 was filed with the patent office on 2007-07-12 for counter-rotating regenerative flywheels for damping undesired oscillating motion of watercraft.
Invention is credited to Gregory Allen Selbe.
Application Number | 20070162217 11/639471 |
Document ID | / |
Family ID | 38019532 |
Filed Date | 2007-07-12 |
United States Patent
Application |
20070162217 |
Kind Code |
A1 |
Selbe; Gregory Allen |
July 12, 2007 |
Counter-rotating regenerative flywheels for damping undesired
oscillating motion of watercraft
Abstract
Pairs of counter-rotating regenerative flywheels (20, 30 and 60,
70) create reinforcing torques when electrical energy is
transferred between the members of a pair. The transfer of
electricity can be controlled to counter undesired oscillations of
a watercraft (10). Motion of the watercraft (10) is sensed by a
sensor system (110), resolved into components and then the
flywheels are controlled to apply torque that counteracts the
undesired oscillation. Preferably, the motion of the watercraft is
evaluated by the sensor in brief increments of one-tenth of a
second or less.
Inventors: |
Selbe; Gregory Allen;
(Honolulu, HI) |
Correspondence
Address: |
CADES SCHUTTE A LIMITED LIABILITY LAW PARTNERSHIP
1000 BISHOP STREET
12TH FLOOR
HONOLULU
HI
96813
US
|
Family ID: |
38019532 |
Appl. No.: |
11/639471 |
Filed: |
December 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60750703 |
Dec 14, 2005 |
|
|
|
60773416 |
Feb 13, 2006 |
|
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Current U.S.
Class: |
701/116 ;
701/21 |
Current CPC
Class: |
G05D 1/0875 20130101;
B63B 39/04 20130101 |
Class at
Publication: |
701/116 ;
701/021 |
International
Class: |
G05D 1/00 20060101
G05D001/00 |
Claims
1. A device for damping oscillations of a watercraft having a roll
axis and a pitch axis, comprising: a pair of counter-rotating
electrically connected regenerative flywheels having parallel axes
of rotation mounted on said watercraft; a regulator controllably
connected to said flywheels; a sensor to sense oscillations of said
watercraft; and a computer connected to said sensor and said
regulator to control said flywheels through said regulator to apply
dynamic damping torque to dynamically damp said oscillations of
said watercraft.
2. A device according to claim 1, wherein said axes of rotation of
said flywheels are parallel to said roll axis of said watercraft,
whereby said flywheels apply dynamic damping torque to dampen roll
oscillations of said watercraft.
3. A device according to claim 1, wherein said axes of rotation of
said flywheels are parallel to said pitch axis of said watercraft,
whereby said flywheels apply dynamic damping torque to dampen pitch
oscillations of said watercraft.
4. A device according to claim 1 or claim 2, wherein said flywheels
are coaxial.
5. A watercraft, comprising: a hull having a roll axis; a first
regenerative flywheel having a first axis of rotation mounted on
said hull with said first axis of rotation parallel to said roll
axis; a second regenerative flywheel having a second axis of
rotation mounted on said hull with said second axis of rotation
parallel to said roll axis and electrically connected to said first
regenerative flywheel; a regulator controllably connected to both
of said flywheels; a sensor for sensing oscillations of said
watercraft around said roll axis; and a computer connected to said
sensor and said regulator to control said flywheels through said
regulator to apply dynamic damping torque to dynamically damp said
oscillations of said watercraft.
6. A watercraft according to claim 5, wherein said first axis of
rotation and said second axis of rotation are the same, whereby
said first flywheel and said second flywheel are coaxial.
7. A process for creating torque to damp undesired oscillations of
a watercraft, comprising: mounting first and second counter
rotating electrically connected regenerative flywheels on said
watercraft; controlling said flywheels to cause one of said
flywheels to generate electricity and decelerate and to apply said
electricity to the other of said flywheels to accelerate, and vice
versa, and to cause said deceleration and said acceleration to
oscillate and damp said oscillations; whereby said oscillating
accelerations and decelerations of said flywheels create
reinforcing torques that damp said oscillations.
8. A process for using pairs of counter-rotating electrically
connected regenerative flywheels having parallel axes of rotation,
comprising: mounting said flywheels on a watercraft to apply
dynamic damping torque to damp oscillations of said watercraft.
9. A device for damping oscillations of a floating watercraft
having a roll axis and a pitch axis, comprising: a pair of
coaxially mounted counterrotating armatures housed in a single
stator, wherein said armatures are provided with sufficient
radially outwardly positioned mass to function as flywheels to
provide damping torque; electrical connections between said
armatures and said stator allowing electricity generated by a
decelerating armature, acting as a generator, to accelerate the
other counter rotating armature, acting as a motor; and a control
system having a sensor to detect roll or pitch motion of a
watercraft and to actuate such armatures to provide angular
momentum to damp such motion.
10. A device according to claim 9, wherein each of said armatures
provides angular momentum substantially equivalent to a ring shaped
mass having an outer diameter of between approximately 48 and
approximately 62 centimeters, an inner diameter of between
approximately 41 and approximately 56 centimeters, a width of
between approximately 7 centimeters and approximately 11
centimeters, and a mass of between approximately 23 kilograms and
approximately 39 kilograms.
Description
[0001] This application claims priority to U.S. provisional patent
application 60/750,703 filed Dec. 14, 2005, incorporated herein by
reference, and to U.S. provisional patent application 60/773,416,
filed Feb. 13, 2006, incorporated herein by reference.
TECHNICAL FIELD
[0002] Oscillating motion is the up and down, or back and forth,
motion of an object connected to, or sitting on, a springy
material, substance or object. Watercraft, such as yachts, personal
and commercial fishing boats, personal recreational boats, ships,
etc., experience undesired oscillating motions, such as pitch
(front and rear going up and down) and roll (right and left going
up and down) caused by surface waves or other forces. These
undesired oscillating motions, also called oscillations, may cause
seasickness, cargo shifting or other motion related problems.
"Damping" (explained below) of oscillations may avoid or reduce
these problems.
BACKGROUND ART
[0003] Oscillations can be reduced by friction or other means, so
that the oscillations become smaller over time. Reduction of
oscillations is called "damping." An example of damping of
oscillations is shock absorbers in cars: shock absorbers reduce the
oscillations a car would experience if it had a suspension system
with springs only; when driving over a bump, a car with broken
shock absorbers bounces up and down many times, but a car with
functioning shock absorbers bounces only once, or a few times.
[0004] In order to dampen oscillations of a watercraft, twisting
forces can be applied to the hull of the watercraft that are timed
in such a way that the twisting forces oppose the direction of the
rolling or pitching motions, therefore partially or completely
damping the oscillations. Because these twisting forces oppose the
oscillation of the rolling or pitching motions, these twisting
forces also oscillate.
[0005] Flywheels store energy of spinning, that is, rotational
kinetic energy. Changing the rotational kinetic energy of a
spinning flywheel is caused by applying torque, that is, a twisting
force. Applying torque in the direction of rotation increases the
rotation rate, and applying torque opposite the direction of
rotation decreases the rotation rate. According to Newton's third
law, for every action, there is an equal and opposite reaction.
Thus, if a twisting force from the shaft or housing of a flywheel
causes the rotational rate of the flywheel to speed up, then the
twisting force also applies an equal and opposite twisting force to
the shaft or housing of the flywheel.
[0006] U.S. Pat. No. 6,234,427 to Decker discloses a satellite
power regulation and pointing system that comprises a power bus and
first and second flywheels capable of storing rotational energy,
wherein each flywheel comprises a flywheel motor/generator for
increasing the rotational energy in its associated flywheel when
storing power in its associated flywheel and for reducing the
associated flywheel rotational energy when drawing power from its
associated flywheel.
[0007] U.S. Pat. No. 5,660,356 to Selfors, et al., discloses a dual
flywheel assembly for use in an airborne vehicle for storing
mechanical energy therein, which includes two flywheels which are
linked by a suitable linkage structure such that, if rolled motion
of the vehicle starts to occur during flight, the flywheel tilts in
equal and opposite directions out of their normal planes of
rotation, which tilting motions act in a passive manner to
stabilize the rolled motion of the vehicle.
[0008] U.S. Pat. No. 4,723,735 to Eisenhaure, et al., discloses an
energy storage attitude control and reference system for a craft,
including at least two flywheels with their angular momenta
balanced to produce zero net angular momentum and at least two
motor/generator units, each including one of the flywheels in its
rotor structure.
[0009] An article entitled "Mechanism of Attitude Control Device
for Floating Object" by Toshiaki Tsuji and Kouhei Ohnishi,
published in Proc IEEE Int Conf Ind Technol, pp. 250-255 (2003)
discloses two coaxial counter-rotating flywheels, each of which is
provided with a brake to increase torque and decrease response time
for attitude control.
[0010] An article entitled "Sensorless Oscillation Control of a
Suspended Load with Flywheels" by Koichi Nishimura, Toshiaki Tsuji
and Kouhei Ohnishi published in 2006 in IEEJ Trans. Ind Appl, vol.
126, No. 8, pp. 1119-1125, discloses applying reaction torque of
flywheels for oscillation control, but this article was published
after at least the earliest provisional application described
above. Reference 6 at the end of this article lists the immediately
preceding article as "A Mechanism on Attitude Control Device for
Flying Object", not "Floating Object."
[0011] An article entitled "Oscillation Control of Suspended Load
with Flywheels" by T. Tsjui and K. Ohnishi published in
Transactions of the Institute of Electrical Engineers of Japan,
Part D, vol. 125-D, no. 6, pp. 548-53, discloses applying reaction
torque of a flywheel for oscillation suppression of a suspended
load using a sensorless estimation method having a bandpass filter.
Applicant may have conceived of his invention before this article
was published.
[0012] An article entitled "A Combined Energy and Attitude Control
System for Small Satellites" published in ACTA Astronautica (ISSN
0094-5765), Volume 54, No. 10, May 1994, pages 701-712), discloses
a double counter-rotating flywheel assembly serving simultaneously
for satellite energy storage and attitude control tasks.
[0013] An article entitled "Hybrid Battery and Flywheel Energy
Storage System for Leo Spacecraft" by B. Beaman, et al., discloses
two counter-rotating wheels used to produce a flywheel energy
storage system that can replace one of the attitude control wheels
in the attitude control system wheel set.
[0014] Mitsubishi Heavy Industries and The Ferretti Group have
developed an anti rolling gyro to reduce the rolling motion of
yachts, as disclosed in "Popular Science", December 2005, page 76,
and the "special projects" section of www.ferrettigroup.com.
DISCLOSURE OF INVENTION
[0015] If a single flywheel is mounted in or on the hull of a
watercraft, then speeding up and slowing down the flywheel will
apply twisting forces to the shaft and/or the housing of the
flywheel, and the shaft and/or the housing will apply twisting
forces to the watercraft itself. For example, if the spinning
flywheel is braked suddenly to a stop using brakes on the shaft or
the housing, the brakes would apply a twisting force to the
watercraft in the same direction as the flywheel was spinning.
[0016] Thus, it is theoretically possible to apply desired twisting
forces to a watercraft by speeding up and slowing down a flywheel.
The flywheel would need to have substantial mass or substantial
rotational speed to generate enough twisting force to affect the
watercraft. The flywheel could be provided with an electric motor
to speed it up, and a brake to slow it down. However, it would
require very substantial amounts of electricity to apply
substantial twisting force to a flywheel with substantial mass or
with substantial rotational speed.
[0017] It is not necessary to position the flywheel on the axis of
the craft--the flywheel can be displaced from the axis and still
provide torque as it speeds up or slows down.
[0018] Certain types of electric motors act as a motor when turning
the shaft of a flywheel, or as a generator if the shaft is rotated
by the flywheel. They are referred to as motor-generators, or
motors, or generators.
[0019] Thus, instead of using a brake to slow down the flywheel, a
rechargeable battery can be used, so that speeding up the flywheel
drains the battery and slowing down the flywheel charges the
battery. This is the principle of regenerative braking used in
hybrid cars. Thus, a flywheel attached to an electric motor (which
can also act as a generator) that can charge a battery is a
regenerative flywheel. A transmission system of gears, chains or
belts may optionally be provided to function between the
motor-generators and the flywheels in order that the
motor-generators may rotate at their most efficient speeds when
accelerating the flywheels as motors or decelerating the flywheels
as generators.
[0020] However, batteries are heavy and inefficient, and the
amounts of energy necessary to create substantial torque are very
high, so the batteries would need to have very substantial storage
capacity.
[0021] Instead of a battery, a second regenerative flywheel could
be used. That second regenerative flywheel could then give and
receive electrical energy from the first regenerative flywheel,
just like a rechargeable battery. Slowing down the first flywheel
by generating electricity would speed up the second flywheel by
applying that generated electricity to the motor for the second
flywheel, and vice versa.
[0022] Further, if the second regenerative flywheel is placed so
that its axis of rotation is parallel to the axis of rotation of
the first regenerative flywheel, and the second flywheel rotates in
the opposite direction from the first flywheel, then the torque
applied to the watercraft by speeding up and slowing down of the
second flywheel will be in the same direction as the torque applied
to the watercraft by slowing down and speeding up of the first
flywheel. Thus, both flywheels will generate torques applied to the
watercraft in the same direction, which will reinforce each
other.
[0023] Accordingly, a pair of counter-rotating electrically
connected regenerative flywheels having parallel axes of rotation
can generate reinforcing torques.
[0024] Two counter rotating, electrically connected, regenerative
flywheels (also called "flywheels" or "flywheel") can therefore be
mounted in or on the hull of a watercraft with their axes of
rotation parallel to each other. If one of the flywheels is made to
act as a generator and the electricity generated is sent to the
motor of the other, the generator flywheel will slow down and the
motor flywheel will speed up. Both flywheels will apply torque in
the same direction to the craft.
[0025] For example, looking from the back to the front, if the
flywheels are mounted with their axes of rotation parallel to the
craft's longitudinal axis, one on the left and one on the right, if
the left flywheel is rotating counterclockwise, and the right
flywheel is rotating clockwise, slowing down the left flywheel to
generate electricity in order to speed up the right flywheel will
create torque in both flywheels in the same counterclockwise
direction. The torque will then apply counterclockwise force to
twist the watercraft. Because electricity can be quickly and easily
transferred back and forth between the flywheels, the torque
generated by the flywheels can be easily reversed in direction, so
that the torque can be made to oscillate, to create an oscillating
torque. Because the torque changes over time, that is, it is not
static, then the torque is dynamic. Thus the flywheels can apply
dynamic damping torque.
[0026] Every craft tends to have a natural frequency, that is, it
tends to roll or pitch at a specific frequency when a force is
applied, as from a surface wave. The paired regenerative flywheels
can be controlled so that they generate oscillating torques at or
near this natural frequency, and in directions opposite to the
oscillations of the watercraft. If the oscillating torques are
strong enough, they can completely cancel out the natural frequency
oscillations of the watercraft.
[0027] Control of the flywheels can be accomplished by providing
sensors to detect the oscillating motion of the craft, and a
computer (including a computer chip, programmable logic controller
or other controlling device) can be provided that controls the
flywheel, through a "regulator". A regulator (including a
motor-generator controller), energizes certain control windings in
the motor-generators in order to cause the motor-generators to
operate as motors or as generators and also to control the speed of
the motors and the amount of energy generated by the generators.
The regulator can be used to control the flywheels so as to apply
oscillating torque that completely or partially cancels or dampens
the detected oscillating motion. Indeed, with appropriate sensors
and control of the current between the regenerative flywheels,
additional torque can be applied as necessary to cancel or dampen
any additional motions that may be detected, so as to provide
dynamic damping torque to damp the additional motions.
[0028] Of course, paired regenerative flywheels can also be placed
on the craft with their axes of rotation transverse to the
longitudinal axis of the craft, to generate oscillating torques
twisting the craft from front to back, to dampen oscillating pitch
motion. However, it is presently preferred to provide only paired
regenerative flywheels to dynamically damp oscillating roll
motion.
[0029] It must be noted that this invention differs from a
gyroscope. A gyroscope will react to an applied torque with a
reaction torque that is 90 degrees away from the applied torque
(called "precession"). By contrast, the counter rotating
regenerative flywheels described herein react to an applied torque
with a reaction torque that is directly opposite the applied
torque. Also, this invention uses counter-rotating pairs of
flywheels, so that any precession from one flywheel is canceled by
the precession from the other.
[0030] Because it may be necessary to transfer such substantial
amounts of electrical current between the regenerative flywheels of
each pair, it is preferred to electrically connect them with bus
bars or other high current connections.
[0031] It is also preferred to use flywheels with high rotational
velocities to reduce the amount of mass of the flywheels.
BRIEF DESCRIPTION OF DRAWINGS
[0032] FIG. 1 is a rear elevational view of a watercraft
conceptually showing a pair of counter-rotating regenerative
flywheels to apply torque for damping roll;
[0033] FIG. 2 is a rear elevational view of the watercraft of FIG.
1 conceptually showing the counter-rotating regenerative flywheels
applying torque to damp a roll to starboard;
[0034] FIG. 3 is a rear elevational view of the watercraft of FIG.
I conceptually showing the counter-rotating regenerative flywheels
applying torque to damp a roll to port;
[0035] FIG. 4 is a top plan view of a watercraft with two sets of
counter-rotating regenerative flywheels, not necessarily to scale,
one for damping roll and one for damping pitch, controlled by a
sensor a computer, and a regulator;
[0036] FIG. 5 is a top plan view of a watercraft with two sets of
counter-rotating regenerative flywheels, one for damping roll and
one for damping pitch, not necessarily to scale, controlled by a
sensor a computer, and a regulator, where the flywheels in each
pair are coaxial.
BEST MODE FOR CARRYING OUT THE INVENTION
[0037] The presently preferred best mode for carrying out the
present invention are illustrated by way of example in FIGS.
1-5.
[0038] Referring to FIG. 1, shown is an elevational view from the
rear of a watercraft 10 with a first regenerative flywheel 20
mounted in a first housing 24 and a second regenerative flywheel 30
mounted in a second housing 34. The first regenerative flywheel 20
and second regenerative flywheel 30 are electrically connected,
preferably by bus bars 56. The first regenerative flywheel 20
rotates in a first direction and the second regenerative flywheel
30 rotates in the opposite direction to form a pair of
counter-rotating regenerative flywheels (as indicated by the
rotational velocity arrows next to the flywheels). As indicated by
the larger hollow arrows, the watercraft 10 may rotate around its
longitudinal (roll) axis in a rotational motion referred to as roll
or rolling. As indicated by the smaller hollow arrows, the first
flywheel 20 and the second flywheel 30 can apply torque to
counteract the roll if the flywheels are accelerated or
decelerated. As indicated by the solid arrow, electrical energy can
be transferred from the first flywheel 20 to the second flywheel
30, or vice versa, over the bus bars 56, to accelerate or
decelerate either flywheel.
[0039] Referring to FIG. 2, shown is the watercraft 10 of FIG. 1
undergoing a rolling motion to starboard (right), so that the
starboard side is lower than the port (left) side. In order to
counteract this roll, it is necessary to apply torque
counterclockwise as indicated by the large hollow arrows. In order
to apply this counterclockwise torque, electricity is transferred
from the first regenerative flywheel 20 to the second regenerative
flywheel 30 over the bus bars 56, as shown by the solid arrow.
Drawing electricity from the first regenerative flywheel 20 slows
down the rotation of the first regenerative flywheel 20 and
accelerates the rotation of the second regenerative flywheel 30 (as
indicated by the rotational velocity arrows next to the flywheels).
Drawing electricity from the first regenerative flywheel 20 is
accomplished by causing it to act as a generator, which causes the
housing 24 to apply a force to slow down that flywheel 20. This
generation of electricity causes an equal and opposite force to be
applied to the first flywheel housing 24, thus resulting in a
counterclockwise torque. Simultaneously, the second regenerative
flywheel 30 is sped up by the electrical energy from the first
flywheel as indicated by the solid arrow, and this acceleration of
the second regenerative flywheel creates an equal and opposite
force on the second flywheel housing 34, again resulting in a
counterclockwise torque. Thus, as can be seen, transferring
electrical energy from the first regenerative flywheel 20 to the
second flywheel 30 results in torque being applied to the first
flywheel housing 24 and second flywheel housing 34 in the same
direction. Accordingly, transferring electrical power from first
flywheel 20 to second flywheel 30 results in reinforcing
torques.
[0040] Referring to FIG. 3, shown is the watercraft of FIG. 1 with
first regenerative flywheel 20 in first flywheel housing 24 and
second regenerative flywheel 30 in flywheel housing 34 with the
watercraft shown rolling to port, so that the port side is lower
than the starboard side. In order to dampen this oscillation, a
torque must be applied in the clockwise direction, as shown by the
large hollow arrows. In this circumstance, second regenerative
flywheel 30 is made to act as a generator to provide electricity
that is transferred over the bus bars 56 to first regenerative
flywheel 20, which causes deceleration of second regenerative
flywheel 30, to create a clockwise torque on the second flywheel
housing 34, and acceleration of first regenerative flywheel 20, to
create a clockwise torque on the first flywheel housing 24 (as
indicated by the rotational velocity arrows next to the flywheels).
Thus, the transfer of electrical energy from second regenerative
flywheel 30 to first regenerative flywheel 20 results in a torque
in the clockwise direction as indicated by the smaller hollow
arrows.
[0041] Referring to FIG. 4, shown is a top plan view of the
watercraft 10 with a first roll flywheel 20, a first roll
transmission system 21, a first roll motor-generator 23 and first
roll control windings 22 housed in first roll flywheel housing 24,
and a second roll flywheel 30, a second roll transmission system
31, a second roll motor-generator 33 and second roll control
windings 32 housed in second roll flywheel housing 34, with axes
parallel to the longitudinal (or roll) axis of the watercraft and
electrically connected by roll bus bars 56, together with a first
pitch flywheel 60, a first pitch transmission system 61, a first
pitch motor-generator 63 and first pitch control windings 62,
housed in first pitch flywheel housing 64, and a second pitch
flywheel 70, a second pitch transmission system 71, a second pitch
motor-generator 73 and second pitch control windings 72, housed in
second pitch flywheel housing 74, with axes parallel to the
latitudinal (or pitch) axis of the watercraft and electrically
connected by pitch bus bars 86. Similar to the first roll flywheel
20 and the second roll flywheel 30, the first pitch flywheel 60 and
second pitch flywheel 70 can provide reinforcing torque to counter
oscillation of the watercraft 10, but this time along the
latitudinal (or pitch) axis of the watercraft.
[0042] A sensor 110, preferably a gyroscopic sensor, is provided
that can sense motion of the watercraft 10. Preferably, the sensor
110 senses motion of the watercraft 10 at intervals of 1/10 second
or less. Information from the sensor 110 is provided to a computer
120 and resolved into roll and pitch components, so that the boat's
oscillation on the roll and pitch axes can be determined. The
computer 120 is controllably connected to the regulator 130 so as
to regulate the control windings 22, 32, 62 and 72 in order to
control the flow of electrical energy between the first roll
flywheel and second roll flywheel and between the first pitch
flywheel and the second pitch flywheel. If desired, a third pair of
flywheels (not shown) can similarly be provided to provide torque
along the yaw (right to left) axis.
[0043] It would be well within the skill of a person of ordinary
skill in the art to select the specific masses and configurations
of the flywheels and the motor generators. Indeed, the flywheels
can be integrally formed with the motor generators for simplicity
and economy of construction and to eliminate transmissions. Motor
generators basically comprise a stator or housing that does not
rotate, a rotor or armature, which rotates within the stator, and
electrical wires wound around the stator and the armature (called
"windings") and connected so that electrical current flowing
through the windings creates interacting magnetic fields in the
stator and the armature that cause the armature to rotate. Thus, if
the rotating armatures of the motor generators have sufficient
radially outwardly positioned mass, the armatures themselves could
function as flywheels and provide damping torque. For example, the
windings are conventionally made of copper, and the armature
conventionally is made of iron and includes spokes or other members
that extend radially outward, with the windings wound around the
spokes or other members. The spokes or other members therefore form
a core around which the windings are wound. The spokes or other
members can be configured so that their mass is concentrated
radially outwardly, if desired, or additional mass can be attached
to radially outward portions of the armature's spokes.
[0044] The integrally formed motor generator and flywheel can be
analyzed as providing angular momentum substantially equivalent to
a rotating ring shaped mass. Using this analysis, accelerating the
rotating armature (of a motor generator) providing angular momentum
that is substantially equivalent to a ring shaped mass (having an
outer diameter of 48 centimeters, an inner diameter of 41
centimeters, a width of 7 centimeters and a mass of 23 kilograms)
from 120 revolutions per minute to 2250 revolutions per minute in
2.5 seconds would produce angular momentum of approximately 250
Newton meter seconds and require approximately 25,000 watts of
power (17 horsepower). When combined with a control system having a
sensor to detect roll or pitch motion of a watercraft (and to
actuate such armatures to provide angular momentum to damp such
motion), two such counter rotating armatures on the same shaft
(with separate bearings to allow the armatures to spin in opposite
directions), within one stator housing, with electrical connections
allowing electricity to accelerate one rotating armature to be
drawn from the other (decelerating) armature acting as a generator,
the combined angular momentum from the armatures can damp the roll
or pitch motion of a watercraft, with a combined angular momentum
from the armatures equal to approximately 500 Newton meter seconds,
enough to provide stabilization for a watercraft having up to
approximately 4500 kilograms (10,000 lbs) of mass. A similar
analysis with an armature providing angular momentum substantially
equivalent to a ring shaped mass (having an outer diameter of 62
centimeters, an inner diameter of 56 centimeters, a width of 11
centimeters and a mass of 39 kilograms), accelerating from 300 RPM
to 1750 RPM in 3.5 seconds would require 31,500 watts of power (21
horsepower) and would produce approximately 1000 Newton meter
seconds, enough to provide damping torque for water craft having up
to approximately 9100 kilograms (20,000 lbs). Larger diameter,
differently shaped and more massive rotating armatures could be
configured as a simple matter of design choice to produce greater
or lesser amounts of angular momentum to stabilize larger
watercraft or smaller watercraft.
[0045] Referring to FIG. 5, shown is a watercraft 10 with first
roll integrally formed motor generator and flywheel 20 and second
roll integrally formed motor generator and flywheel 30, but mounted
coaxially and housed in a single roll flywheel housing 24.
Optionally, first pitch integrally formed motor generator and
flywheel 60 and second pitch integrally formed motor generator and
flywheel 70 are coaxially mounted in a single pitch flywheel
housing 64. Again, a sensor system 110 and a computer 120, which is
controllably connected to the regulator 130 are provided in order
to control the flow of electrical energy between the first roll
flywheel 20 and second roll flywheel 30 and the optional first
pitch flywheel 60 and optional second pitch flywheel 70 along bus
bars connecting them.
[0046] The present invention has been disclosed in connection with
the presently preferred best modes described herein, but it will be
obvious to those skilled in the art that various changes may be
made in the disclosed preferred embodiments without departing from
the spirit and scope of the invention. Accordingly, no limitations
are to be implied or inferred in this invention except as
specifically set forth in the attached claims.
INDUSTRIAL APPLICABILITY
[0047] This invention can be used whenever it is desired to provide
a force to counteract or damp undesired oscillation and other
motion.
* * * * *
References